Gear



March 8, 1932.

d. E. GLEASON GEAR ' Filed May 22, 1929 lNVENTOR JAMES E. GLEASONATTORNEYC Patented Mar; 8, 1932 v PATENT oF l JAMES E. GLEASON,OF'ROGHESTER, NEW YORK, ASSIG-NOR TO GLEA'SON WORKS, OF ROCHESTERQNEWYORK, A'CORPORATION OF NEW YORK GEAR ' Application filed may 22, 1929.,seria fno. 365,014.

' The present inventionf relates to tapered gears, bevel and hypoidgears,and particular- The purposeof the presentiinvention' is to ly todouble spiral or herringbone tapered gears.

providea form ofdoublespir'al orherringbone tapered gear which will beeasy toma-n ufacture and stronger than any prior'proposed form of suchgears.

o With the present invention, the gears are madein twoparts and theteeth on the inner portion are inclined at an angle to the teeth 7 onthe outer portion to provide, whenthe two parts are secured together,the double- 5. helical or herringbone tooth. Theinnerp'ortion is madewith fewer teeth than the outer portion, that is, the inner portion willhave a coarser pitch thantheouterportion This. construction providestapered gears of great er'strength than tapered gears as heretoforemanufactured, for witha tapered gear'ofithe usual construction theteeth'are, of the same pitch throughout their. length, i and the teethtaper". in height and thickness from the r outer to their inner ends. lV

Ina pair of gears constructed according to this invention, the outerportions of the two f meshing gears will be of the same pitch-and theinner portions of the two gears will be of the same pitch but ofafdifierent pitch from the outer portions; This means, that the ratio inwhich:

Figure, 1

I V is a side elevation showing, a pair of; double-helical or herrngbone bevel gears constructed according ;to this invention in mesh; andq Figure, 2;-is afragrnentarysectional view through the rear axle of anautomotive vehiber 20 of thepinion has 12 teeth.

cle showing an application of the present invention'to the rearaxledrive of a motor'car.

10 designates the gear or larger member I of the pair and 11 the pinion,The gear is made in two parts, an outer portion'12 and an inner portion13. Each portion is toothed I and the teeth of the two portions areinclined at an angle to each other to provide, when i' the twoparts aresecured together, the double helical or herringbone toothrform'. The twoportions 12 and 13have, different numbersof teeth. Preferably, the innerportion 13 has fewer teeth than the outer -portion, th'at is, is ofcoarser pitch thanthe outer portion. With this construction, the innerportion and,

therefore, the whole gearwill .be stronge i. I

than herringbone bevel gears of prior types, in which thepitch, thatis,the number 'of, teeth in the inner portionisthe same as on I theouterportion and in which due'to the taper of the teeth, the gear is weakerat its inner than at its outer end. The'present in vention provides agear,the inner portion of;

which is just as strong as the outer portion;

Preferably, the teeth of the two portions are longitudinally curved andpreferably curved on opposite hands. In the gear shown, the I teeth 15ofthe toothportion 12 are of right- I hand curvature and the teethleoftheinner portion'l3 are of left hand curvature. v

' Like the gear, the pinionll is made in two parts,- an outerportion 20and an inner portion 21. The inner portion 21 corresponds in pitch tothe inner portion 13 of the gear 10 i and is, ofcoarser pitch than theouter portion 2O ofthe pinion which corresponds in pitch 7 to the pitchof the outer portion 12 of the gear: Thus, the ratio of the innerportions 21 and 13 is the sameas the ratio of the outer.

portions 20 and l2 so that when the inner mating gear of the pair. Inthe pair shown, the outer member 12 of the gear 10 has 48 teeth and theinner member of this same geartO teeth, while the inner member 2l 'ofthe pinion 11 haslO teeth and the outer mem- The teeth 24: of the innerportion 21 of the pinion are curved lengthwise in anopposite and outerportions of each gear are secured together they will mesh as one gearwith the ring gear with reference'toeach other fortne same purpose byinterposing a shim under direction from the curvature of theteeth of theouter portion 20 of the pinion, that is, are of opposite hand. Ofcourse, the hands of the two portions of the pinion are opposite fromthe hands of the portions of the gear with which each, respectively,mesh. The inner portion 21 of the pinion has teeth of right hand and theouter portion 25 of the pinion teeth are left hand. This particularcombination is preferred for forward drives as the inner portion 21 ofthe pinion will then thrust inward and the outer portion 25 outward. l

Preferably, the two portions of each gear will be out as spiralbevelgears with generated tooth profiles. This method ofv cutting has theadvantage of quickness and simplicity and in addition the gears can becut on existing machinery.

The load carried by the inner and outer portions of the gears can bebalanced so that each portion of each gear will carry the same load atany point in the face. This can be done, for instance, by making thespiral angle of the inner portion greater than the spiral angle of theouter portion.

Figure 2 shows the gears of my inventionin use in a rear axle drive. Thetwo parts of the rear axle are indicated at and 31, respectively. Theusual .form of differential connecting the two halves of the axle isdesignated M32; 7 The two parts 12 and 13 forming thering gear aresecured to thediiferen tial housing 33 by the screws or bolts 34 and 35.The two portions 20 and 21 of the drive pinion are mounted" on thepropeller shaft 36 in such way as to rotate with the'propeller shaftthrough the key connection indicated at 37. Nuts 38'and 39 which arethreaded on the ropeller shaft serve totake the thrusts of t e twohalves of the pinion. A shim 41 of the required size is interposedbetween th portions20 and 21-.

Aside'from" the low cost which is a feature of a pair where the twoparts ofeach gear are cut as spiral bevel gears and secured togetherthere isthe advantage, not present in any form of herringbone bevelswhere the two portions. are made integral, that by making the gearsintwo parts, a proper tooth bearing can readily besecured. Thus, the gearand pinion can be mounted on a testing machine in the shop and runtogether and allowed to adjust themselves until a proper tooth bearingis secured. When the proper tooth bearing is secured, the shim 41 willbe selected to a size to retain this tooth bearing when the gears aremounted in the axle and it is also possible 'to adjust the parts 12' and13 of the one orother of these parts between the back of the part andthedifferential" housing.

While the invention has been described in connection with a particularembodiment and and as may be applied to the essential featureshereinbefore setforth' and as fall within the scope of the invention orthe limits of the nded claims. aving thus described my invention,what 1. A tapered gear comprising outer and innor members havinglongitudinally curved teeth, the teeth of one member being.difi'erently' inclined from the teeth of the other member-to a linedrawn radially of the apex of the gear, and the inner member having asmaller number of teeth than the outer member.

' 2. A tapered gear comprisingouter and inner members havinglongitudinally curved teeth of opposite hand, the inner member being ofa larger pitch than the outer member and havin a larger spiral anglethan the outer mem er. e I i 3. A pair of tapered gears, each of whichconsists of an outer member and an inner member whose teeth are inclinedat different angles to a straight line drawn from the apex of thegear,'thenumberof teeth in the inner member of each gear being less thanin the outer member of the same gear but the ratio of teeth in the outermembers being the same as in the inner members.

4. A pair of tapered gears, each of which comprises an outer and aninner member whose teeth are longitudinally curved and'inclinedatdifl'erent angles to a straight line drawn from the apex of the gear,the inner member of each gear having less teeth than the outer member ofthe same gear, but the ratios of inner members and outer members beingequal. I

' 5. A pair of tapered-gears each of which consists of an inner memberand an outer member havinglongitudinally curved teeth of oppositehands,.the number of teeth in the inner member of each gear being lessthan in the outer member of the same gear but the ratios of inner andouter members being equal.

6. A pair of tapered gears, each of which comprises an inner member andan outer member having longitudinally curved teeth, the hands of saidmembers being di fierent and the spiral angles of the teeth of thesmaller-members being larger than the spiral anglesof the teeth of'thelarger member, said inner members having fewer teeth than theirrespective outer members, but the ratio of the inner members beingequalto the ratio of the outer members; v I I 7. A tapered gear having atoothed por tion comprising two sections of difierent numbers of teeth,the section atthesmaller' end of the gear-having the smaller numberofteeth I J v 8. A tapered gear having its toothed portion formed in twoparts,'the teeth of the 1 two parts being oppositely inclined. to oneanother and having difi'erentnumbers of teeth, the part at the small endof the gear having the smaller number of teeth. I

' 9. A tapered gear having its toothed portion formedin two, the teethon the two being;

oppositely inclined to one another and having different numbers-ofteeth, the-part at I the inner end of the gear having the smaller numberof teeth, and the teeth of said inner,

part being more inclined to a generatrix of the pitch surface of thegearthan the teeth r of the outer part. 7 I 1 V JAMESE. GLEASON,

